Petrucci is set to miss this weekend's Argentina round, next weekend's Austin event and perhaps even the first European round at Jerez after the stress of riding re-damaged his right hand during practice in Qatar.

Stoner had offered to replace Repsol Honda's Dani Pedrosa at the same events one year ago, prompting speculation he might make the same offer in his new role as a Ducati test rider.

But location aside, the circumstances are very different.

Stoner had four years of past experience with the RC213V, including racing it in 2011 and 2012, and would have been returning to the official factory Honda team in place of his friend Pedrosa.

By contrast, at the time of his decision not to step in for Petrucci, Stoner had only ridden the Ducati/Michelin/single ECU package once, and would have been racing last year's GP15 rather than the 2016 factory bike.

Qatar runner-up Dovizioso - a former team-mate to Stoner at Honda, now working with him again at Ducati - confirmed: "With Casey anything can happen, but after the race in Qatar it was clear that he didn't want to race.

"Also I think he couldn't find what he want to race, in the Pramac team. Because the rules say he would have to use the [GP15] bike of Pramac. So I think there wasn't a reason to do that."

The MotoGP rules state: 'Should a rider be replaced for any reason, the replacement rider will be deemed to be the original rider for purposes of engine allocation.' In other words, the replacement must use the spec of engine sealed for the permanent rider at the start of the year. In Petrucci's case, GP15 engines.

There would also have been a question mark over Stoner's race fitness at such short notice, having suffered injuries at last year's Suzuka 8 Hours and then kidney problems in October. Although typically fast during his Ducati return at Sepang, the 30-year-old Australian admitted he was "suffering" physically.

"When he start with the [Ducati] tests I consider the possibility [that Stoner will] make some races, no?" Rossi said. "But reading and hearing what Stoner said, he said that he don't want to race. I think this is the truth, but for the rest I don't know more than that."

Although he has consistently denied any plans to race again, Ducati's door is certainly not closed to such a move should Stoner have a change of heart later in the season. As a wild-card Stoner would be free to use the latest Ducati machinery, including '3 engines for exclusive use
during each event'.